dopamine

Craving in the Modern World: How Environmental Disruptions Hijack Our Biology and Drive Overeating

The conventional narrative of human eating behavior often suggests that we overeat because we are hardwired to crave calories for survival. This view implies that obesity is an inevitable byproduct of evolutionary programming, a relic from our ancestors who needed to store fat for times of scarcity. However, this explanation oversimplifies the complexities of human behavior, psychology, and the modern environment.

As Mark Schatzker argues in The End of Craving, while humans require calories to survive, our biological programming doesn’t inherently drive us to overconsume them. Instead, the environmental disruptions of the modern world manipulate our behaviors, reshape our psychology, and lead to the widespread obesity crisis. The interplay between these factors has created a perfect storm, overriding natural regulatory systems and fostering patterns of overconsumption largely disconnected from biological needs.

Human evolution prioritized efficiency over excess. Early humans lived in environments where food was scarce, and physical activity was constant. While carrying extra fat may have been advantageous during periods of famine, it also came with significant drawbacks. As Schatzker highlights, a greater body mass reduced agility, increased the risk of injury, and made individuals more vulnerable to predators. Excessive weight also hindered the ability to chase and capture prey, diminishing survival odds.

Traits that favored energy balance—efficient use of calories rather than unchecked consumption—were far more advantageous. To support this balance, humans evolved intricate systems of energy regulation, including hunger and satiety signaling, which were fine-tuned for natural food environments. These systems worked well in environments where foods were whole and minimally processed. But today, hyper-engineered food landscapes exploit these systems, disrupting the balance that evolution worked so meticulously to create.

Dana Small, a leading expert in neuropsychology and nutrition science, has shed light on how modern food environments distort our biology. Her research on "nutritive mismatch" reveals how ultra-processed foods hijack the body’s natural regulatory systems. In her groundbreaking experiments, Small demonstrated that when sweetness—a cue for incoming calories—does not align with actual caloric content, metabolic processes falter.

Small created a series of solutions with varying calorie amounts, all designed to taste equivalently sweet, mimicking the caloric content of 75 calories of sugar. Remarkably, only the solution where sweetness matched caloric content triggered the body’s expected metabolic response, efficiently burning the calories. Mismatched solutions—where sweetness falsely signaled caloric content—showed no such response. This disruption, which Small terms “nutritive mismatch,” illustrates how processed foods confuse the body, leaving it unable to metabolize calories effectively. In natural food environments, sweetness reliably indicated energy, and the body responded accordingly. Today, these mismatched cues foster cycles of overconsumption, as the body perpetually chases an equilibrium it can no longer find.

Small’s findings challenge the assumption that overeating is a natural behavior. Instead, they reveal that the modern food environment manipulates our biological systems, encouraging patterns of eating disconnected from genuine physiological needs. This disruption is compounded by the psychological dynamics of craving, a distinction Schatzker emphasizes in his work.

Hunger is a biological drive designed to meet energy needs, while craving is a psychological state driven by the brain’s reward system. Cravings are fueled by dopamine, the neurotransmitter associated with anticipation and reward. In the context of food, dopamine surges in response to cues like the sight or smell of hyper-palatable options, triggering an intense desire to eat. Yet, these foods often fail to deliver the satisfaction the body expects, creating a disconnect between “wanting” and “liking.” This cycle mirrors addiction, where the relentless pursuit of reward becomes disconnected from actual satisfaction.

Repeated dopamine surges condition the brain to seek out ultra-processed foods—not because they nourish, but because they promise a fleeting reward. Over time, this psychological shift transforms eating into a pursuit of gratification rather than a response to hunger. The modern food environment, with its hyper-palatable, mismatched offerings, capitalizes on this vulnerability, driving a feedback loop of overconsumption and dissatisfaction.

The obesity crisis, then, cannot be reduced to an evolutionary imperative to overconsume calories. It is the product of environmental disruptions that exploit human biology and psychology, distorting natural regulatory systems. Small’s research on nutritive mismatch and Schatzker’s insights into craving illuminate the profound impact of these factors, offering a more nuanced understanding of why we overeat in the modern world.

A Heads-Up Look at Brain Health

Medical advances of today and the very near future — gene therapies, nanotechnology, targeted monoclonal antibodies, cloning, and more — will allow us to “repair” or “replace” damaged and diseased body parts and raise the average life expectancy to 100 years or more. The problem with this magnificent advancement is the studies which suggest that 40% of those reaching 85, and nearly 100% of those reaching 120, will be senile. Of what use is living to a ripe old age if we cannot enjoy it, or even be aware that we’re alive?

Brain Studies

Some 2000 years ago the ancient Greeks attributed all behavior to four temperaments: Hot, Dry, Moist, and Cold. The Romans attributed all symptoms and behaviors to four body fluids, which they called humors: Phlegm, Yellow Bile, Black Bile, and Blood. While Hippocrates, Galen, and hundreds of others slowly advanced the understanding of human anatomy and physiology, the brain sat unstudied for over 1500 years. It was not until the 18th and 19th centuries that brain anatomical science progressed to the point that four distinct lobes were identified, with specific behaviors and body functions ascribed to each.

Over the next 100 years, biochemical and pharmaceutical researchers discovered four separate brain chemicals, called neurotransmitters, that were used by the brain. Somewhat later, four distinct brain waves, or patterns of electrical activity, were discovered and correlated with specific lobes in the brain. Only fairly recently have researchers started to understand this most mysterious organ.

From the 1950s to present, psychiatrists and phychologists have described four broad classifications of human behavior: extroverted or introverted, intuitive or sensing, thinking or feeling, and perceiving or judging. If you suspect that these four primary behaviors can be assigned to a specific lobe, you’d be right!

Brain malfunctions, as manifested by psychiatric problems or unacceptable behavior, can be largely attributed to an imbalance of neurotransmitters within the brain. Unfortunately, discovering these levels within a living brain was not an easy task. (If you think a spinal tap is a risky procedure, just imagine a “brain tap” gone wrong!) What was needed was a simple, noninvasive test to measure the levels of neurotransmitters in a functioning human brain. Various scans of the brain can be employed, but they cannot show actual brain function. For example, an MRI of a patient’s brain right before death and right after death would be identical.

After 25 years of painstaking work, neurological researchers have finally uncovered a long-hidden piece of the puzzle — the relationship between the brain’s chemicals and the brain’s electricity. This discovery allowed clinicians to diagnose brain dysfunction with a simple, noninvasive assessment of the brain’s electrical activity. By measuring the four electrical components of brain activity, doctors can determine the levels of the four neurotransmitters and initiate treatment protocols to correct a deficiency of one or more of them.

Correlation Times Four

Four temperaments; four humors; four neurotransmitters; four lobes; four classes of human behavior; four brain waves; four electrical measurements of brain function. How do these relate? The following table shows the relationship between brain lobes, neurotransmitters, behaviors or personality types, and electrical measurements.

The table above shows the electrical measurements used to determine neurotransmitter levels. As a person ages, his brain goes through a slow decline, or “electropause,” in which the voltage, speed, rhythm, and synchrony change. By measuring these four electrical characteristics, a person’s “brain age” can be determined, which may be younger or older than typical for his chronological age. More importantly, a deficiency in one or more neurotransmitters can be detected and steps taken to restore normal levels.

A computerized diagnostic device called a Brain Electrical Activity Map (BEAM) measures these four values and creates a “picture” of the brain’s electrical activity. It records and tracks the progression of the positive wave created in the brain by an external stimulus, such as a sound (auditory evoked potential) or a flash of light (visual evoked potential).

Speed. A “normal” brain takes about 300 msec (milliseconds) plus a person’s age in years to “think.” This is the measurement of the time delay, or latency, between a stimulus given and the recognition of that stimulus in the brain. As the latency increases (speed decreases), a person moves from mild cognition deficits to severe dementia.

Voltage. A “normal” brain creates an electrical potential of about 10 µv (microvolts). The voltage generated in a person’s brain is related to his ability to concentrate, and low voltage can result in memory impairment, obesity, addictions, or schizophrenia.

Rhythm refers to the regularity of a person’s brain waves. Like cardiac rhythm, the more smooth the rhythm, the better. Brain-wave arrhythmias yield a spectrum of disorders from anxiety and recurring headaches to manic depression and seizures.

Synchrony is a comparison of the electrical activity in each of the hemispheres of the brain. It is common for a person to be dominant in one hemisphere or the other, but a severe imbalance in the electrical activity of the right vs. left hemisphere can lead to sleep disorders, IBS, somatization disorders, or phobias.

Acetylcholine

Review: A “normal” brain takes about 300 msec (milliseconds) plus a person’s age in years to “think.” This is the measurement of the time delay, or latency, between a stimulus given and the recognition of that stimulus in the brain. As the latency increases (speed decreases), a person moves from mild cognition deficits to severe dementia.

Acetylcholine-associated disease states

A diagnostic evaluation of a person’s brain speed can give objective evidence of disturbances in cognition, memory, attention, and behavior. After subtracting the patient’s age, the baseline latency measurement indicates the following: 300 msec is “normal”; 350 msec indicates mild to moderate disturbances in cognitive function (“muddled thinking”); 360 to 370 msec indicates ADD or variability of attention, errors of omission or commission, and delayed reaction time; 380 msec is typically found in Parkinson patients; 420 msec is the threshold for Alzheimer disease, with increasing latency as the dementia progresses. Early detection of deficiencies in the speed at which the brain operates can allow early intervention to slow or reverse the decline, possibly delaying or preventing the onset of Alzheimer and other dementias.

Beyond detecting a frank disease state associated with severe acetylcholine deficiency, physicians can analyze thebalance of the four neurotransmitters to determine a patient’s personality type.

The acetylcholine-dominant personality

Acetylcholine is produced in the parietal lobes, which are responsible for thinking functions such as language processing, intelligence, and attention. People with an excess of acetylcholine (about 17% of the world’s population) are adept at working with their senses and view the world in sensory terms. They are quick thinkers, highly creative, and open to new ideas. Flexibility, creativity, and impulsivity open them up to trying almost anything, as long as it offers the promise of excitement and something new; they are not afraid of failure. They love to travel and have a quest for lifelong learning. These people also tend to be extremely sociable, even charismatic. They love making new friends and put a lot of energy into all of their relationships, whether at work, at home, or in the community. They are eternally optimistic, romantic with their significant other, and attentive to the needs of their children. They are quite popular with a broad range of people. People with extremely high levels of acetylcholine, however, risk giving too much of themselves to others, even to the point of being masochistic. They may feel that the world is taking advantage of them, or they may become paranoid. Too much acetylcholine can drive a person into isolation.

The acetylcholine-deficient personality

Low levels of acetylcholine result when either the brain burns too much or produces too little. Shifts in personality occur at a much milder deficiency than the dementia- producing deficiencies mentioned earlier. These personality traits can, in fact, manifest when the acetylcholine level is only slightly lower than the levels of the other three neurotransmitters. And remember, we’re looking at the relative balance of neurotransmitters. A deficiency in one neurotransmitter is usually offset by an excess of another, which typically produces the personality traits associated with a dominance of that other neurotransmitter.

The eccentric. The absence of thought connections to other people and the world makes this person’s behavior seem odd. The eccentric usually steers away from human interaction and keeps himself isolated. Outwardly, he appears bland and inexpressive. When even mildly stressed, however, he can become a danger to himself and others.

The perfectionist. This person is usually hard working, detail oriented, devoted, and exacting. Self-discipline is a hallmark of this personality type, which can be either a plus or a minus, depending on the severity of the imbalance and which other neurotransmitter is dominant. This person can be an excellent worker, or he can be rigid and obsessive to the point that nothing is actually accomplished. The perfectionist’s life is usually lacking in enjoyment, relaxation, and warmth, which can make that person unapproachable.

Dopamine

Review: A “normal” brain creates an electrical potential of about 10 µv (microvolts). The voltage generated in a person’s brain is related to his ability to concentrate, and low voltage can result in memory impairment, obesity, addictions, or schizophrenia.

Dopamine-associated disease states

A person’s ability to concentrate can be directly correlated with his dopamine level. A diagnostic evaluation of the voltage in a person’s brain can give objective evidence of disturbances in concentration and memory. Low dopamine levels can be involved in difficulty performing routine tasks, a variety of sexual disorders such as loss of libido or anorgasmy, various addictions, from caffeine to opiates, and decreased physical activity due to fatigue. Obesity is a common result of the combination of sugar cravings and low physical activity associated with suboptimal dopamine levels in the brain.

Brain voltage can vary within the range of 0 µv (dead) to 20 µv (super concentration), with 10 µv being classified as “normal.” The voltage range correlates as follows: 0-2 µv is typically found in cocaine babies; 2-4 µv can indicate severe addictions, severe attention deficit disorder, or schizophrenia; 5-6 µv indicates a chronic brain disorder; 7 µv is found in those with moderate addictive behavior, such as caffeine and sugar cravings; 8-9 µv is typical for mild to moderate memory and thinking disturbances, including mild attention deficit; 10 µv is “normal”; and above 10 µv indicates an increased ability to concentrate, even to the rejection of external stimuli at the high end of the range.

Drugs that increase dopamine levels have been used as adjunctive therapy for schizophrenia and opiate addiction. Beyond detecting and treating frank disease states associated with a severe dopamine deficiency, physicians can analyze the balance of the four neurotransmitters to determine a patient’s personality type.

The dopamine-dominant personality

Dopamine is the source of the brain’s power and energy. People with an excess of dopamine (about 17% of the world’s population) thrive on energy. They are likely to be strong-willed individuals who know what they want and how to get it. They are highly rational, more comfortable with facts and figures than feelings and emotions. They can be self-critical, but do not accept criticism or negative feedback from others. These people function well under stress, focusing intently on the task at hand. They are tireless and typically need less sleep than average. Strategeic thinking, invention, and problem-solving are the hallmarks of these individuals. In their personal lives, they like activities related to knowledge and intellect. They can be competitive in sports, but prefer individualized sports over group sports. They tend to establish personal relationships easily, but may have trouble nurturing them. As highly rational people, they have trouble understanding that many people believe feelings are more important than reason. They have a tendency to want to exert control over their spouse and children, and a successful marriage depends on the loyalty and goodwill of the spouse.

People with extremely high levels of dopamine, however, can be overly intense, driven, and impulsive. They may turn to violence as a way of creating controlled environments of excitement and power. Teens may be driven to shoplifting, street racing, or date rape. Criminals — especially repeat sexual offenders — often have extreme dopamine levels and a heightened libido that frequently accompanies it.

The dopamine-deficient personality

Low levels of dopamine result when either the brain burns too much or produces too little. Shifts in personality occur at a much milder deficiency than the disease- producing deficiencies mentioned earlier. Personality shifts can, in fact, manifest when the dopamine level is only slightly lower than the levels of the other three neurotransmitters. And remember, we’re looking at the relative balance of neurotransmitters. A deficiency in one is usually offset by an excess of another, which typically produces the personality traits associated with a dominance of that other neurotransmitter.

Dopamine production determines the brain’s power, as measured by voltage. As the voltage becomes suboptimal, the person literally slows down, mentally and physically. Minor deficiencies can produce a range of mental and physical symptoms, such as mild memory loss, mild depression (“the blues”), panic disorder, PMS, insomnia, fatigue, mild hypertension, nicotine addiction, and obesity. Sexual side effects, such as loss of libido and difficulty achieving orgasm, are common among people with a dopamine deficiency.

The previous two neurotransmitters — acetylcholine and dopamine — can be thought of as the brain’s “on” switch, providing energy, power, and speed. The next two — gamma-aminobutyric acid (GABA) and serotonin — function as the brain’s “off” switch, providing calmness, rest, and sleep. A balance of the “on” and “off” neurotransmitters is necessary for proper brain function.

GABA

Review: Rhythm refers to the regularity of a person’s brain waves. Like cardiac rhythm, the more smooth the rhythm, the better. Brain-wave arrhythmias, or dysrhythmias, yield a spectrum of disorders from anxiety and recurring headaches to manic depression and seizures.

GABA-associated disease states

Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the brain. It has a calming, stabilizing effect. It controls the brain’s rhythm, which allows a person to function at a steady pace and prevent him from becoming too “hyper.” As the brain’s GABA level declines, brain waves begin to become less rhythmic. This can bring on a multitude of symptoms, both psychological and physical.

Mild brain-wave dysrhythmias can produce anxiety and its accompanying physical manifestations: restlessness, sweating, cold or clammy hands, butterflies in the stomach, and a lump in the throat. Other physical symptoms that can appear with a moderate GABA deficiency include carbohydrate cravings, an abnormal sense of smell, and unusual allergies. As GABA levels further decrease, anxiety can become more pronounced and produce attention-deficit disorders, PMS, flushing, trembling, hypertension, cystitis, and gastrointestinal disorders. At the most extreme deficiency, this can become full-blown panic attacks, manic depression, migraine headaches, hyperventilation, palpitations, tachycardia, blurred vision, tinnitus, twitching, and seizures. Advanced psychological symptoms can include severe delusions, feelings of dread, and a short temper that can progress into full-blown rage reactions and violence. Chronic marijuana and alcohol abuse can signal an acute GABA deficiency.

Beyond detecting and treating frank disease states associated with GABA deficiencies, physicians can analyze thebalance of the four neurotransmitters to determine a patient’s personality type.

The GABA-dominant personality

People with high GABA levels (about 50% of the world’s population) share the common attributes of stability, consistency, sociability, and concern for others. They are nature’s most dependable people. They can be counted on to show up at work every day and be there when others need them. At work, GABA- dominant people are the ones who set goals, organize projects, schedule activities, and keep others on task. Their punctuality, objectivity, practicality, and confidence make them excellent employees. Organization is paramount to them — at work, at home, and in their social life. It’s no wonder that these people gravitate to careers as administrators, accountants, air-traffic controllers, meeting planners, nurses, EMTs, and yes, medical transcriptionists. They’re the ones in the group who stay focused on the matter at hand. They are the consummate team player, both metaphorically and literally. In their personal life, such people derive pleasure from taking care of their family and friends. They can be a serene island in a sea of chaos. Although they like group activities, they cherish one- on- one relationships. Their friends are forever, and their marriage is a long- term commitment. Nurturing and making others happy is their ultimate goal. They tend to be religious and believe in traditions, especially where friends and family are involved, such as holiday gatherings.

As with the other neurotransmitters, it is possible to have too much of a good thing. People who produce too much GABA can be organizational to the point of setting rigid schedules and micromanaging others, whether as a boss, a coworker, a friend, or spouse. Excess GABA can dramatically increase a person’s nurturing tendencies. They can spend enormous amounts of time and energy looking for opportunities to give love and care to others, at the cost of their own needs not being met.

The GABA-deficient personality

Low levels of GABA result when either the brain burns too much or produces too little. Shifts in personality occur at a much milder deficiency than the disease- producing deficiencies mentioned earlier. Personality shifts can, in fact, manifest when the GABA level is only slightly lower than the levels of the other three neurotransmitters. And remember, we’re looking at the relative balance of neurotransmitters. A deficiency in one is usually offset by an excess of another, which typically produces the personality traits associated with a dominance of that other neurotransmitter.

Unlike a balanced brain that creates energy in a smooth, steady flow, a person with low GABA creates energy in bursts. This brain dysrhythmia can upset the body in a number of ways, but none is more pronounced than in the realm of emotional well- being. Specifically, he can lose the ability to effectively deal with life’s stresses. He may begin to feel nervous, anxious, and irritable. He may demonstrate poor emotional stability, lack impulse control, and resort to childish behavior. It can also manifest as poor verbal memory and difficulty concentrating. Physically, low GABA levels can bring on a variety of subacute conditions such as allergies, transient aches, instability while walking, diarrhea or constipation, and insomnia or hypersomnia. Usually, such physical annoyances occur one after another to the point that a person begins to wonder about his general state of health.

Serotonin

Review: Synchrony is a comparison of the electrical activity in each of the hemispheres of the brain. It is common for a person to be dominant in one hemisphere or the other, but a severe imbalance in the electrical activity of the right vs. left hemisphere can lead to sleep disorders, IBS, somatization disorders, or phobias.

Serotonin-associated disease states

Correlating with delta waves in the brain, serotonin affects your ability to rest, regenerate, and find serenity. Adequate serotonin allows the brain to recharge and rebalance itself each night, so that you can begin each morning with a fresh start. Serotonin is produced in the occipital lobes, which is also the center of sight.

As serotonin levels drop, the right and left hemispheres become desynchronized, producing feelings of being out of control. Moderately low levels can produce depression, mild hypertension, arthritis, poor temperature regulation, sexual disturbances such as premature ejaculation or delayed arousal response, bowel disturbances, mild PMS with emotional outbursts, learning disorders, obsessive- compulsive behavior, and insomnia, which tends to further lower serotonin levels. As levels drop further, hypertension can become uncontrolled, arthritis can intensify, PMS can become severe, and a wide range of perimenopausal symptoms can occur. With a severe shortage of serotonin, physical and psychological disturbances may become life threatening, with bingeing, masochism, severe depression and other serious mood disorders, addictions including alcoholism and drug abuse, somatization disorders, schizoaffective disorders, and schizophrenia with hallucinations. Physically, a severe serotonin deficiency can cause insomnia/ hypersomnia sleep cycles measured in days and increase hypertension to the point of producing a stroke.

Beyond detecting and treating frank disease states associated with serotonin deficiencies, physicians can analyze the balance of the four neurotransmitters to determine a patient’s personality type.

The serotonin-dominant personality

People with high serotonin levels (about 17% of the world’s population) know how to live in the moment. Realistic and impulsive, they are highly responsive to sensory input. They’re active participants in life who thrive on change. They take their vacations at a different spot each year. They try new foods, new hobbies, and new friends, and they have a natural disdain for order, structure, and authority. They’re optimistic, cheerful, easygoing, and the life of the party. A serotonin-dominant person gravitates to trades or professions that offer a variety of tasks, an ever-changing environment, and interactions with different people. Their keen hand-eye coordination makes them well suited to using various tools to accomplish their tasks. Construction workers, truck drivers, military personnel, hairstylists, pilots, surgeons, chiropractors, movie stars, fashion models, photographers, and professional athletes likely owe their skills to ample serotonin levels. Preferred sports can include mountain climbing, hunting, skydiving, hang gliding, scuba diving — just about anything that offers a personal challenge along with a certain level of excitement. They play hard and have the time of their life when doing activities that others would consider too dangerous. In relationships, they can be romantic and passionate, but they also love their independence and often refuse to be tied down. Due to their impulsivity and desire for change, they tend to move away from people before deep relationships develop. In fact, their friendships are typically many and varied — wide instead of deep. They have a fondness for children, but make better aunts and uncles than parents.

As with the other neurotransmitters, it is possible to have too much. An excess of serotonin can make a person extremely nervous. He can become hesitant, distracted, hypersensitive to criticism, and morbidly afraid of being disliked. Excessive serotonin can make a person believe he is inadequate and inferior. Sadness and anger are constant companions, and although he may have a desperate desire for interpersonal interaction, he is too fearful to even make an attempt.

The serotonin-deficient personality

Serotonin deficiency can occur from experiencing too much excitement (thereby metabolizing large amounts of serotonin) and/or not getting sufficient sleep (causing the brain to generate less serotonin). Shifts in personality occur at a much milder deficiency than the disease- producing deficiencies mentioned earlier. Personality shifts can, in fact, manifest when the serotonin level is only slightly lower than the levels of the other three neurotransmitters. And remember, we’re looking at the relative balance of neurotransmitters. A deficiency in one is usually offset by an excess of another, which typically produces the personality traits associated with a dominance of that other neurotransmitter.

A common sign of serotonin deficiency is depression and fatigue. The chronic lack of sufficient sleep means that the brain is unable to rest, regenerate, and resynchronize. This can manifest in the personality as a flat affect (a classic sign of depression) and a lack of pleasure, artistic appreciation, and common sense. The person may become codependent, obsessive- compulsive, or exhibit loner tendencies. He can be impulsive or perfectionistic, painfully shy or masochistic. Someone with multiple phobias is typically serotonin deficient. The frequent use of ecstasy, PCP, and LSD also signals a serotonin deficiency.

Lettin’ the good guys in,
Keepin’ the bad guys out

We have been made with a wonderful mechanism to prevent harmful substances from entering the brain. Not everything that circulates in the blood stream is allowed entry into the brain. There is a barrier between the blood and the brain, logically called the blood-brain barrier, that allows only glucose and certain nutrients selective access to the brain. This membrane protects the brain from toxins and other substances that would cause it damage. It also “holds in” certain substances manufactured by the brain, notably neurotransmitters, that would be lost through diffusion throughout the rest of the body if allowed to pass into the blood stream. Therefore, the same membrane that prevents toxins from passing through also prevents neurotransmitters from passing through. This characteristic of the blood-brain barier is the reason why a Parkinson disease patient, for example, cannot receive an injection of dopamine to restore the dopamine level in his brain and reverse the disease. So the dilemma is how to raise the level of specific neurotransmitters in the brain, when simple supplementation with those neurotransmitters is ineffective.

The answer lies in finding a way to “coax” the brain to produce more endogenous neurotransmitters. It turns out that the answer is fairly simple — give the brain more raw material, and it will make more neurotransmitters. Fortunately, the mechanism by which the brain makes each neurotransmitter is well known. Like most substances in the body, they are made through a series of chemical reactions. Notice that I said the blood-brain barrier allows only glucose and certain nutrients selective access to the brain. It is those “certain nutrients” that the brain uses to make neurotransmitters. If there is a deficiency in any of the nutrients needed to make a specific neurotransmitter, there will be a corresponding deficiency of that neurotransmitter. Supplementing the deficient nutrient(s) will allow the brain to resume full production of the neurotransmitter.

Building a better brain

So what are the “certain nutrients” that the brain must have? Without going into the chemistry of neurotransmitter manufacture, suffice it to say that the brain’s supply of amino acids is the most common limiting step in their production. Amino acids, the basic building blocks of protein, are also the basic raw material the brain uses to function. As such, they easily cross the blood-brain barrier. All amino acids can cross the blood-brain barrrier, in fact, but not all are used to make neurotransmitters. The problem is that all the amino acids circulating in the blood stream at any given time compete for passage through the “amino acid channels” in the blood-brain barrier, and passage of a specific amino acid is granted in proportion to its concentration in the blood. If you eat a steak or other complete protein source, all 20 amino acids are simultaneously competing for entry into the brain. Supplementing with, say, 1 gram of a certain amino acid won’t do much if you chase it with a glass of milk (15 grams of protein in 12 oz.) or take it with a meal. To be effective, amino acid supplements should be taken on an empty stomach with plain water or fruit juice (the fructose in juice helps escort the amino acid to the brain).

In the paragraphs that follow, I will tell you which amino acids are used to boost which neurotransmitter, and the primary food sources for that amino acid. Food sources are complex, however, and foods that boost the production of one neurotransmitter can also contain substances that boost the production of another. Eggs, for example, provide a tremenous boost for acetylcholine, but they also have a component that supports GABA. This is one reason why a change of diet takes longer to produce an effect than supplementation with pure amino acids. You should know that prescription drugs are also available to boost the production of a specific neurotransmitter or slow its destruction, but that is beyond the scope of this article. They are listed in detail in the reference given at the end of the article. (Note: numbers shown after the supplements listed below refer to the relative efficacy in boosting the neurotransmitter, on a scale of [1]=best to [4]=least effective.)

Boosting acetylcholine

  • Pure amino acid precursors: serine, carnitine.
  • Amino acid-boosting supplements: DMAE (dimethylaminoethanol) [1], phosphatidylcholine [1], phosphatidylserine [2], acetyl-L-carnitine [2], GPC (glycerol phosphocholine) [3].
  • Supporting supplements: huperzine A [1], nicotine [1], lipoic acid (alpha-lipoic acid) [3], fish oils [3], manganese [4], conjugated linoleic acid [4].
  • Hormonal supplements: DHEA (dehydroepiandrosterone) [2].
  • Illegal supplements: LSD, PCP, psychotropic mushrooms.
  • Dietary support: choline-rich foods, including avocado, cucumber, zucchini, lettuce, most fruit, bacon, bologna, hot dogs, chicken, turkey, pork, liver, fish, beef, milk, ice cream, sour cream, yogurt, cheese, eggs, and various nuts.
  • Lifestyle support: aerobic exercise.

Boosting dopamine

  • Pure amino acid precursors: phenylalanine, tyrosine.
  • Amino acid-boosting supplements: N-acetyl tyrosine [2], L-tyrosine [3], phenylalanine [3]. (Note: most ingested phenylalanine is hydroxylated to tyrosine in the body. Tyrosine supplements, therefore, need one less chemical conversion step to be used by the body.)
  • Supporting supplements: caffeine [1], guarana [1], yohimbe [1], ephedra[2], nicotine [2], Rhodiola rosea[3], thiamine [4], chromium [4], folic acid [4].
  • Hormonal supplements: DHEA [2].
  • Illegal supplements: cocaine, ecstasy, mescaline.
  • Dietary support: phenylalanine- and tyrosine-rich foods, including wild game, duck, turkey, pork, chicken, luncheon meats, cottage cheese, ricotta, milk, yogurt, walnuts, soybeans, wheat germ, granola, rolled oats, dark chocolate, and eggs.
  • Lifestyle support: sexual activity (for women), weight-bearing exercise, aerobic exercise.

Boosting GABA

  • Pure amino acid precursor: glutamine.
  • Amino acid-boosting supplements: L-glutamine [1].
  • Supporting supplements: inositol [1], alcohol [1], B vitamins [2], glycine [3], kava [3], BCAA (branched-chain amino acids) [4], taurine [4].
  • Hormonal supplements: progesterone [2].
  • Illegal supplements: opioids, ketamine, marijuana, quaaludes.
  • Dietary support: glutamine-rich foods (especially complex carbohydrates), including almonds, walnuts, and other tree nuts, whole-grain wheat and oats, rice bran, brown rice, lentils, potatoes, broccoli, spinach, bananas, citrus fruit, halibut, and beef liver.
  • Lifestyle support: sexual activity (for men and women), sleep, aerobic exercise.

Boosting serotonin

  • Pure amino acid precursor: tryptophan.
  • Amino acid-boosting supplements: L-tryptophan [2], 5-HTP (5-hydroxytryptophan) [3].
  • Supporting supplements: St. John’s wort [2], vitamin B6 [4], fish oils [4].
  • Hormonal supplements: melatonin [1], progesterone [2].
  • Illegal supplements: LSD, PCP, GHB, ecstasy.
  • Dietary support: tryptophan-rich foods, including wild game, pork, luncheon meats, duck, turkey, chicken, wheat germ, cottage cheese, and eggs.
  • Lifestyle support: aerobic exercise, psychotherapy, sleep.

To learn more

This series of articles is a synopsis of the groundbreaking research of Eric R. Braverman, MD, as presented at the American Academy of Anti-Aging Medicine (A4M) Annual Conference, June 2003. Dr. Braverman was a member of the pioneering research team at Havard University that developed the BEAM (Brain Electrical Activity Map), a noninvasive device to measure neurotransmitter levels in functioning brains through electrical activity. For more information, his book, The Edge Effect, is highly recommended reading.